In 747 a major rebellion broke out against the Umayyad Caliphate, which ruled most of the Middle East from 661 to 750. The principal cause of the rebellion was the increasing gap between the outlying peoples of the Caliphate and the Damascus-based Umayyad government. The Umayyad-appointed governors of the Caliphate's various provinces were corrupt and interested only with personal gains. Additionally, the Umayyads claimed no direct descent from Muhammad, while the Abbasids did (they descended from Muhammad's uncle Abbas—a fact the latter used greatly during the revolution).